Long Term Evolution (LTE) is a new network scheme recommended by the 3rd Generation Partnership Project (3GPP). In an LTE network, all communications are carried over an IP channel from user equipment (UE) to an all-IP core called the Evolved Packet Core (EPC). The EPC then provides gateway access to other networks while ensuring an acceptable Quality of Experience (QoE) and charging a subscriber for their particular network activity.
The 3GPP generally describes the components of the EPC and their interactions with each other in a number of technical specifications. Specifically, 3GPP TS 23.203, 3GPP TS 29.212, 3GPP TS 29.213, and 3GPP TS 29.214 describe the Policy and Charging Rules Function (PCRF), Policy and Charging Enforcement Function (PCEF), and Bearer Binding and Event Reporting Function (BBERF) of the EPC. These specifications further provide some guidance as to how these elements interact in order to provide reliable data services and charge subscribers for use thereof. The 3GPP specification allows the Policy and Charging Control (PCC) architecture to interwork with older generation networks (e.g., General Packet Radio Service (GPRS)). For example, 3GPP TS 29.212 and 3GPP TS 29.214 provide some guidance on the establishment of an application session by the EPC upon receipt of an application request from an Application Function (AF) in the form of an AA-Request (AAR) message or from a Packet Data Network Gateway (PGW) in the form of a Credit Control Request (CCR) message. The standards specify that the PCRF is responsible for receiving new service requests, creating new PCC rules commensurate with such requests, and providing these new PCC rules to a Policy and Charging Enforcement Function (PCEF) for installation. The 3GPP standards also define the format of service request messages and PCC rules.
The 3GPP specifications suggest that the PCRF-provided authorized QoS at the Internet Protocol Connectivity Access Network (IP-CAN) bearer level, at the QoS Class Identifier (QCI) level and the service flow level. The 3GPP specifications further specify that the level at which the PCRF provides the authorized QoS is based on the bearer control mode—if PCRF or PCEF is responsible for the PCC rule binding—a process of which a PCC rule is bound to a specific IP-CAN bearer. As per the 3GPP specifications, the PCRF provides the authorized QoS at the IP-CAN bearer level when the PCRF does bearer binding (i.e., Bearer control mode is UE-only), and provides the authorized QoS at the QCI level when the PCEF does bearer binding (i.e., Bearer control model is UE_NW). The authorized QoS at the service flow level is provided by the PCRF in both bearer control modes.
The 3GPP specification suggests that the provisioned authorized QoS per QCI applies independently to all IP-CAN bearers with the same QCI, currently active, within the same IP-CAN session. This 3GPP-suggested method provides inefficiencies as the PCRF may not have a complete view of the active IP-CAN bearers at the PCEF or the PCC rule(s) currently bound to them. The problem relates to authorizing QoS per QCI in the mixed mode operation (i.e., Bearer control mode is UE_NW). As per the 3GPP specifications, the Policy and Charging Rules Function (PCRF) may provide Authorized QoS per QCI for the non Guaranteed Bit-Rate (GBR) IP-CAN bearers, when the PCEF performs bearer binding.
Therefore, a more efficient means of managing resources and distribution of bandwidth in an LTE system is highly desirable.